Inspecting materials for uniformity and detection of anomalies is important in disciplines ranging from manufacturing to science to biology. Inspection often employs microscope inspection systems to examine and measure electronic objects on a substrate (e.g., a wafer) or features of a biological specimen mounted on a slide. Specimens as understood by a person of ordinary skill in the art refer to an article of examination (e.g., a wafer or a biological slide). Electronic objects on a substrate can include devices such as transistors, resistors, capacitors, integrated circuits, microchips, etc. Biological specimens are typically mounted on slides for microscopic inspection. Objects, as understood by a person of ordinary skill in the art, has a broad meaning as provided in the specification and recited in the claims, and can refer to electronic objects on a substrate or biological objects such as cells, tissue or the like found in a biological specimen mounted on a slide among others. Although the following description refers to examining objects on a substrate that are electrical in nature, the automatic mapping described herein can be used to examine biological specimens and objects mounted on slides.
Microscope inspection systems can be used to image objects on a substrate for later analysis. To facilitate accurate analysis, it is helpful to capture consistent images of like objects, or consistent images of an object and its reference template (sometimes referred to as a golden template). For example, if an object is smaller than the field of view of an imaging device, then like objects can be aligned in the same way in relation to an imaging device, so that captured images of the like objects all show similar alignment of the imaged object (referred to herein as “imaging alignment position”). In one embodiment, as shown for example in FIGS. 1A and 1B, the upper left corner 115, 115 of objects 120, 120 each appears in the upper left corner of the field of view of an imaging device, represented by a single square 110, 110. Although the orientation of object 120 has rotated, field of view 110 has rotated as well, to maintain the same alignment of objects 120 and 120 in the captured images.
Note, the term field of view as understood by a person of ordinary skill in the art is in the context of digital microscope and refers to an area of examination that is captured at once by an image sensor. Further, a person of ordinary skill in the art will readily understand that the terms field of view, image and tile are used interchangeable herein.
In another example, as shown in FIG. 2, when an object 220 on substrate 310 exceeds the field of view of an imaging device, as represented by each tile 215, then a sequence of images (e.g., tiles 1-18) might be needed to capture the entire object. Note, field of view and tile are used interchangeably herein. To facilitate accurate analysis, it is helpful to capture the sequence of images in a consistent manner, with a similar imaging alignment position, across like objects or compared to a reference template. In one example, a first image can be captured starting at a specific feature on the object or at a specific location (e.g., upper left corner 115) on the object (referred to herein as the “starting scan position” and indicated by *) and subsequent images can be captured, for example, in a predefined sequencing path (e.g., in a serpentine manner as indicated by sequencing path 230 as shown on FIG. 2). Each image in the sequence can be assigned a number (e.g., 1-18) and images with the same number can be compared across like objects or to a reference template.
Knowing the exact position and orientation of each object and/or features of the objects on a substrate can facilitate correct alignment of a stage, imaging device and object to capture images where like objects are consistently aligned within the field of view, or a similar sequence of images are captured for like objects. Aside from image capture, knowing the position and orientation of an object and/or feature of an object on a substrate can be useful for various stages of a manufacturing or an examination process and/or for anomaly analysis. In some embodiments, an object can have indicators on the object itself to help determine the orientation of the object (e.g., asterisk (*) 225a that appears in the upper left corner and plus sign (+) 225b that appears in the lower right corner of specimen 220).
An initial object layout map can specify the X, Y, θ coordinates of each object on a substrate (“expected position” or “original position”). For example, X, Y can refer to a coordinate position of each object 220 in relation to a common reference point on a substrate (e.g., an origin point), and θ can refer to the orientation of each object 220 or a biological specimen in relation to an origin point relative to a known coordinate system, as explained further within. However, an initial object layout map typically does not account for movement (i.e., movement is referred to in the specification and claims as “fluid” and means that an object is capable of movement from an original position to a later position) of the objects during examination and/or manufacturing process from their initial X, Y, θ coordinates. When printing objects on a bendable or elastomeric (“flexible”) substrate (e.g., polymide, PEEK or transparent conductive polyester film), printing a flexible object (e.g., a flexible OLED), examining fluid biological specimens mounted on a slide and/or examining objects post-dicing (e.g., on a hoop ring, Gel-Pak®, waffle pack), the objects can shift from their original or expected X, Y, θ coordinates (e.g., as specified in an initial object layout map). Deformation of a flexible substrate and/or flexible object can also occur, which can also alter the expected X, Y, θ coordinates of objects on a substrate or biological specimens on a slide. Deformation (also known as morphing by a person of ordinary skill in the art) can refer to deviations between an object and a reference object in overall dimensions and/or individual features of the objects. The reference object can refer to a reference template image for that object type and/or an earlier version of the object.
Accordingly, it is desirable to provide new mechanisms for automatically mapping fluid objects on a substrate (e.g., by determining the X, Y, θ coordinates of each object on a substrate) to locate objects that have shifted from their expected coordinates on a substrate (e.g., as compared to an initial object layout map), as well as to predict X, Y, θ coordinates of an object on a substrate at different stages in an examination or manufacturing process.